I'm pretty sure he means number of posts per hour.

How do you check number of posts?

10PM (754 posts, including this one)9PM (701 posts)6PM (680 posts)8PM (630 posts)7PM (614 posts)11PM (604 posts)5PM (591 posts)4PM (545 posts)1AM (530 posts)12AM (473 posts)2AM (368 posts)3PM (314 posts)3AM (301 posts)2PM (266 posts)1PM (236 posts)12PM (190 posts)4AM (171 posts)11AM (98 posts)6AM (89 posts)7AM (87 posts)10AM (85 posts)5AM (58 posts)9AM (40 posts)8AM (28 posts)